Annunciator.



W. M. DAVIS. ANNUNCIATOB.

-(App1ication filed Dec. 16, 1899.)

'No. 655,763. Patented Aug. l4, 1900.

(No Model.)

W1 l LHL LL Q. \A/n. 1AM MJIIAVIE ATTDRTLEIE THE Mamas Fun: 00.PNQYO-LITNO.. WASHINGTON. D c.

WILLIAM M. DAVIS, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE STROMBERGCARLSON TELEPHONE MANUFACTURING COMPANY.

AINNUNCIATQR.

s'rncirroarron forming part of Letters Patent No. 655,763, dated August14, 1900. Application filed December 15, 1899. $erial No. 740,414. (Nomodel.)

To all whom it may concern.-

Be it known that I, WILLIAM M. DAVIS, a citizen of the United States,residing at Chi cago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Annunciators, (CaseNo.2,) of which the following is a full, clear, con- 'cise, and exactdescription, reference being had to the accompanying drawings, formingto a part of this specification.

My invention relates to annunciators, and

has for one object the provision of an improved a form of annunciatoremploying an armature and a target-lever wherein the armature is I 5confined to a very small range of movement, so that the annunciator maybe operated with small current, the lines of force essential foreffecting the attraction of the armature having to bridge a very smallair-gap between the armature and the poles of the electromagnet.

My invention has for a further object the provision of an improvedmounting for the pivots of the armature, so that the said piv- 2 5 otsmay be readily secured in position with out having to be separatelyfastened in place.

Generally speaking, my invention comprises an annunciator provided withan armature pivoted at one end of the electromagnet, comprising a partof the annunciator, the

pivotal support for the armature being preferably located slightly abovethe center or axis of the coil of said electromagnet, so as to enablethe armature to actuate the target- 3 5 lever through a shorter range ofmotion than was heretofore accomplished. The target-lever preferablycarries a target which is bodily movable therewith and upon which anindicating-number may be placed as is desired, as is well known to thoseskilled in the art.

When the annunciator of my invention is to be employed in connectionwith telephoneexchaiige systems, I preferably surround the same by amagnetic sheath of iron to'prevent induction of voice currents from onecoil to another. In order that the pivotal supports for the armature maybe readily assembled in place, I mount the same upon a collar and slipthe collar over the end of the magnetic sheath, a single screw or otherfastening means serving to secure the collar in place.

It is obvious, however, that this same supporting-collar could heslipped directly over the magnet-coil if the coil should be unprovidedwith a sheath. By these means each pivotal support does not require aseparate fastening. The collar supporting the same also ser,ves tomaintain the said pivots in their properrelative positions.

I will explain my invention more fully by reference to the accompanyingdrawings, in which Figure 1 is a side elevation of my improvedannunciator, an alternative position of the target-lever being indicatedby dotted lines. 6 5 Fig. 2 is a plan view of the annunciatorillustrated in Fig. 1, circuit connections of the annunciator with atelephone-line being illustrated. Fig. 3 is a side elevation, partiallyin section, of the annunciator. Fig. 4 is an end vi ew of theannunciator, showing my improved armature-mounting; Fig. 5 is an endView with the armature and its pivots removed.

Like partsareindicated by similar letters of reference throughout thedifferent figures.

The annunciator shown is provided in this instance with a singleelectromagnet whose terminals are led through tubes at Ct to permit theannunciator to be connected with a suitable circuit-such as isillustrated, for example, in Fig. 2, where the terminals of theannunciator-coil are connected with the back contacts of a spring-jackswitch Z2, connected with the telephone line to enable a subscriber 8 5to include the annunciator in circuit with a suitable source of current.

The annunciatorcoil is provided with a magnetic sheath 0, having a capat at one end.

A collar e incloses the sheath at the other end, 0 being secured theretopreferably by a screw f. (Removed for the sake of clearness from Fig.3.) I use the term-.inclosing in the claims in the sense of a collarthat either completely or partially surrounds the armature- 9 5 coil, asit is obvious that the same result can be secured by eitherconstruction. This collar is provided with two rearwardly and inwardlyextending ears 9 g, which are located slightly above the diameter of thecoil. Each 1co ear is provided with an inner rearward extension h, asshown most clearly in Figs. 1, 2

2 states and 4:. The extensions hare provided with threaded holesextending transversely of the annunciator for receiving the pivot-screws2', the pivot-screws being opposed and located slightly above thediameter of the sleeve e. The extensions h are preferably slotted, asindicated. The lower half portion of the sheath or sleeve 0 projectsslightly to the rear and forms a segmental pole-piece 7c. The armature Zis similar in outer contour to the pole-piece 7c and is provided withcurved recesses for accommodating the tubes at a. The armature proper ispreferably pivoted directly upon the screws i rl, as shown most clearlyin Figs. 2 and 4:, this portion of the armature being reduced in width,the portion of the armature below the diameter of the coil beingpractically semicircular.

I believe it is new with me to make a pole of the electromagnet in theform of a segmental sleeve-section.

Strips of metal wt, preferably iron, are secured to the armature to actas a counterbalance and to serve as a means of securing one end of thetarget-lever n to the armature, the other end of the target-levercarrying a target 0. A collar 13 of insulating material surrounds thecore q of the electromagnet, the core projecting beyond the collar andforming a second pole-piece. An adjustingscrew 1" passes through thearmature and the counterbalancing-plate secured thereto and is adaptedfor direct engagement with the insulating-collar p. A set-nut sisemployed to secure the screw in any position to which it may beadjusted. When circuit is closed through the annunciator, the magneticcircuit is completed by way of the core q, the armature, and theprojecting portion 7c of the sleeve.

By the construction shown it is obvious that the lines of force threading the air-gap between the armature and the opposed magneticportions do not have to be greatly shortened to effect the desiredmovement of the armature and target-lever.

I have herein shown and particularly described one embodiment of myinvention; but it is obvious that other features of construction couldbe devised without departing from the spirit of the invention, and I donot therefore wish to be limited to the precise construction shown; but,

Having thus described my invention, I claim as new and desire to secureby Letters Patent-= 1. In an annunciator, the combination with anelectromagnet, of a segmental pole-piece 7." in the form of asleeve-section, a core q for the electromagn et projecting beyond thesame and partially surrounded by the sleeve-section is, a pivotedarmature arranged in jux taposition with the said core and portion 7a,and a target-lever secured to the armature, substantially as described.

2. In an electromagnet, the combination with a coil, of a segmentalsleeve-section for conveying lines of force set up by the said coil,inwardly-projecting pivot-bearings located above said sleeve-section,and located between the periphery and axis of the annunciator, and anarmature opposed to the said sleeve-section, substantially as described.

3. In an annunciator, the combination with an electromagnet, of a sleevee inclosing the same provided with pivot-supporting exten sions h,screws 2, *5, carried by the said extensions, an armature supported bythe pivots, and a target-lever secured to the armature, substantially asdescribed;

4. In an annunciator, the combination with an electromagnet, of a sleeve6 inclosing the same, the said sleeve being provided withinwardly-projecting ears g, g, the said ears being provided withrearwardly-projecting extensions h, h, pivots 2', 2' carried by theprojections h, h, an armature held between the said pivots, and atarget-lever secured to thearmature, substantially as described.

5. In an annunciator, the combination with an electromagnet, of a sleeve6 inclosing the same, the said sleeve being provided withinwardly-projectin g ears g, g, the said ears being provided withrearwardly-projecting extensions h, h, pivots 2', 1' carried by theprojectionsh, 72, an armature held between the said pivots, atarget-lever secured to the said armature, and a segmentalsleeve-section 7c of magnetic material for, receiving lines of force setup by the electromagnet opposed to the lower end of the armature, thesaid lower end of the armature being shaped substantially to conform incontour to the said sleeveseotiou, substantially as described.

In witness whereof I hereunto subscribe my name this 11th day ofDecember, A. D. 1899.

WILLIAM M. DAVIS.

Witnesses:

GEORGE L. ORAGG, CHARLES E. HUBERT.

ICC

